ACOM1308.pdf (18.31Mb)

(1)

ICES

ADVISORY

C

OMMITTEE

ICES CM 2008/ACOM:13

Report of the Working Group on Widely Distributed Stocks (WGWIDE)

2–11 September 2008

ICES Headquarters Copenhagen

(2)

International Council for the Exploration of the Sea Conseil International pour l’Exploration de la Mer

H. C. Andersens Boulevard 44–46 DK‐1553 Copenhagen V

Denmark

Telephone (+45) 33 38 67 00 Telefax (+45) 33 93 42 15 www.ices.dk

[email protected]

Recommended format for purposes of citation:

ICES. 2008. Report of the Working Group on Widely Distributed Stocks (WGWIDE), 21 – 1 September 2008, ICES Headquarters Copenhagen. Diane. 67 pp.

For permission to reproduce material from this publication, please apply to the Gen‐

eral Secretary.

The document is a report of an Expert Group under the auspices of the International Council for the Exploration of the Sea and does not necessarily represent the views of the Council.

(3)

Contents

Executive Summary ...viii

1 Introduction ...1

1.1 Terms of Reference ...1

1.2 List of Participants ...3

1.3 Quality and Adequacy of Fishery and Sampling data ...4

1.3.1 Sampling Data from Commercial Fishery ...4

1.3.2 Importance of métier identification...17

1.3.3 Catch Data...18

1.3.4 Discards...18

1.3.5 Age‐reading ...20

1.3.6 Biological data ...21

1.3.7 Quality Control and Data Archiving...22

1.3.8 InterCatch...26

1.4 Checklists for quality of assessments...28

1.5 Comment on update and benchmark assessments...28

1.6 The ICES stock handbook...40

1.7 Reference points relevant for WGWIDE...40

1.8 Blue Whiting...40

1.8.1 Blue Whiting Management Plan Evaluation...40

1.8.2 Answer to special request on NEA mackerel...44

1.8.3 Irish request on long‐term management for North East Atlantic mackerel ...47

1.9 Ecosystem considerations for widely distributed and migratory pelagic fish species ...48

2 Northeast Atlantic Mackerel...58

2.1 ICES advice applicable to 2007 and 2008...58

2.2 The Fishery in 2007...59

2.2.1 Catch Estimates ...59

2.2.2 Discard Estimates...62

2.2.3 Fleet Composition in 2007 ...63

2.3 Stock description and management units NS, Western Southern ...63

2.4 Data available...65

2.4.1 Catch data ...65

2.4.2 Effort and Catch per Unit Effort ...66

2.4.3 Survey Data ...67

2.4.4 Length Composition of Catch ...72

2.4.5 Weights at age in the catch and stock ...73

2.4.6 Maturity Ogive...73

2.4.7 Mortality estimates from tag recaptures...74

2.5 Methods ...75

(4)

2.5.1 FLICA assessment method ...76

2.5.2 Bayes method for evaluation of potential missing biomass and removals from the NEA mackerel population. ...76

2.5.3 Short term forecast and yield per recruit analysis...78

2.6 NEA Mackerel Reference points...78

Current Reference points from ICES advice 2007 ...78

2.7 State of the stock ...79

2.7.1 Final ICA Assessment ...79

2.7.2 Bayesian analysis unaccounted mortality ...80

Bayesian analysis unaccounted mortality...80

2.8 NE Mackerel Catch predictions for 2008 ...82

2.9 Uncertainties in assessment and forecast ...84

2.9.1 Uncertainties in assessment...84

2.9.2 Uncertainties in forecast...84

2.10 Comparison with previous assessment and forecast...85

2.11 Management plans and evaluations ...86

2.11.1Harvest Control Rules...86

2.11.2Results of evaluations...87

2.12 Management Considerations ...88

2.13 Ecosystem considerations...89

2.14 Regulations and their effects ...91

2.15 Changes in fishing technology and fishing patterns ...91

2.16 Changes in the environment...92

3 Horse Mackerel ...183

3.1 Fisheries in 2007 ...183

3.2 Stock Units...184

3.3 Allocation of Catches to Stocks...184

3.4 Estimates of discards...185

3.5 Trachurus Species Mixing...186

3.6 Length Distribution by Fleet and by Country: ...186

4 North Sea Horse Mackerel (Divisions IVa,b,c, IIIa, and VIId) ...198

4.1 ICES advice Applicable to 2007 ...198

4.2 The Fishery in 2007 on the North Sea stock ...198

4.3 Fishery‐independent Information ...198

4.3.1 Egg Surveys ...198

4.4 Biological Data ...199

4.4.1 Catch in Numbers at Age ...199

4.4.2 Mean weight at age and mean length at age...199

4.4.3 Maturity at age ...199

4.4.4 Natural mortality ...199

(5)

5 Western Horse Mackerel (Divisions IIa, IIIa (Western Part), IVa, Vb,

VIa, VIIa–c, VIIe–k, AND VIIIa‐d...205

5.1 ICES advice Applicable to 2007 and 2008...205

5.1.1 Stock description and management units ...206

5.2 Scientific data ...207

5.2.1 The fishery in 2007...207

5.2.2 Egg survey estimates of spawning biomass...207

5.2.3 Effort and catch per unit of effort ...209

5.2.4 Catch in numbers ...210

5.2.5 Mean length at age and mean weight at age...210

5.2.6 Maturity ogive...210

5.3 Methods ...210

5.3.1 Data exploration...210

5.3.2 Simulation testing of SAD ...211

5.3.3 Preliminary modelling ...212

5.4 Reference points...215

5.5 State of the Stock...216

5.5.1 Stock assessment ...216

5.5.2 Reliability of the assessment ...216

5.6 Short‐term forecast ...217

5.7 Uncertainties in the assessment and forecast...217

5.10 Management considerations ...218

5.14 Changes in the environment ...219

6 Southern Horse Mackerel (Division IXa)...254

6.1 ICES advice applicable to 2007 and 2008...254

6.2 Stock description and management units ...255

6.3 Scientific data ...255

6.3.1 The fishery in 2007...255

6.3.2 Fishery independent information...256

6.3.3 Effort and catch per unit of effort...258

6.3.3 Effort and catch per unit of effort ...259

6.3.4 Mean length at age and mean weight at age...260

6.3.5 Maturity at ageCatch in numbers at age...260

6.4 Information from the fishing industry...261

6.5 Methods ...261

(6)

6.5.1 The ASAP model...261

6.5.2 Model and data exploration ...262

6.7.1 Stock assessment ...264

6.8 Short term forecast...264

6.9 Uncertainties in assessment and forecast ...265

6.12 Management plan evaluations...266

7 Sardine general ...302

7.1 The fisheries for sardine in the ICES area...302

7.1.1 Catches for sardine in the ICES area ...302

7.2 Catch and survey data for sardine in areas VIIIa and VIIIb ...303

7.2.1 Catch data in areas VIIIa and VIIIb ...303

7.2.2 Acoustic survey in areas VIIIa and VIIIb...304

7.2.3 Biological data ...306

7.3 Future of assessment and management of sardine outside the stock area ...306

8 Sardine in VIIIc and IXa...333

8.1 ACFM Advice Applicable to 2007 ...333

8.2 The fishery in 2007...334

8.2.1 Fleet Composition in 2007 ...334

8.3 Fishery independent information...335

8.3.1 DEPM – based SSB estimates ...335

8.3.2 Acoustic surveys ...336

8.4 Biological data ...338

8.4.1 Catch numbers at length and age ...338

8.4.2 Mean length and mean weight at age ...338

8.4.3 Maturity and stock weights at age ...338

8.5 Effort and catch per unit effort ...339

8.6 Relevant information on ecological/environmental studies related to sardine ...339

8.6.1 Ecosystem considerations...339

8.6.2 Recruitment forecasting and Environmental effects...339

(7)

8.7.1 Data exploration...340

8.8.1 Stock assessment. ...341

8.8.2 Reliability of the assessment ...342

8.9 Catch predictions ...342

8.9.1 Divisions VIIIc and IXa ...342

8.10 Reference points for management purposes...343

8.12 Towards a management plan for sardine...344

9 Norwegian spring spawning herring...398

9.1 ICES advice in 2007 ...398

9.2 The fishery in 2007...398

9.2.1 Description and development of the fisheries ...398

9.2.2 Information on bycatches in the fisheries...399

9.2.3 Denmark...399

9.2.4 Germany...399

9.2.5 Greenland...399

9.2.6 Faroe Islands...399

9.2.7 Iceland ...400

9.2.8 Ireland ...400

9.2.9 Netherlands ...400

9.2.10Norway...401

9.2.11Poland...401

9.2.12Russia...401

9.2.13UK (Scotland) ...402

9.3 Stock description and management units ...402

9.3.1 Stock description...402

9.3.2 Changes in migration ...403

9.3.3 Management in 2008...403

9.4.1 Catch data ...404

9.4.2 Information from the fishery...405

9.4.3 Weight at age...405

9.4.4 Natural Mortality...405

9.4.5 Maturity at age ...406

9.4.6 Fisheries independent information ...407

9.5 Data exploration and prelimary assessment...411

9.5.1 Methods...411

9.5.2 Results of data analyses and exploration ...415

9.5.3 Exploratory assessment runs...416

9.5.4 Comparison TASACS with Seastar and TISVPA ...419

9.6 Final assessment...419

9.7.1 Precautionary and limit reference points: ...420

(8)

9.7.2 Target reference points...420

9.9.1 Input data for the forecast ...421

9.9.2 Results of the short term forecast ...421

9.10 Medium term forecasts ...422

9.11 Uncertainties in the assessment and forecast...422

9.13.1History of the management plan ...423

9.17 Changes in fishing patterns...424

9.19 References...427

10 Blue Whiting...528

10.1 ICES advice in 2007 ...528

10.2 The fishery in 2007 and 2008 ...528

10.2.1Denmark...528

10.2.2Germany...528

10.2.3Faroe Islands...528

10.2.4Iceland ...529

10.2.5Ireland ...529

10.2.6Netherlands ...529

10.2.7Norway...529

10.2.8Russia...530

10.2.9Spain ...530

10.2.10 Portugal ...530

10.3 Blue Whiting Stock description and management units ...530

10.3.1Blue Whiting Stock Identity ...531

10.4.1Catch data ...532

10.4.2Information from the fishing industry...534

10.4.3Weight at age...535

10.4.4Maturity and natural mortality...535

10.4.5Fisheries independent data...536

10.5 Methods ...540

10.5.1Data exploration in SMS ...540

10.5.2Data exploration in FLICA ...542

10.5.3Data exploration in TISVPA ...542

10.5.4Data exploration in XSA ...543

(9)

10.6 Final assessment...544

10.7 Biological reference points ...545

10.8 State of the Stock...546

10.9.1Recruitment estimates ...546

10.9.2Short term forecast...547

10.10Medium term forecasts ...548

10.11Uncertainties in assessment and forecast ...548

10.12Comparison with previous assessment and forecast...548

10.13Management plans and evaluations ...549

10.13.1 Evaluation of the MP proposal by the blue whiting Coastal states ...549

10.13.2 Possible effects of protecting juvenile blue whiting ...555

10.14Management considerations ...556

10.15Ecosystem considerations...557

10.16Regulations and their effects ...558

10.17Changes in fishing technology and fishing patterns ...559

10.18 Changes in the environment...559

11

Recommendations ...633

12

References ...635

13 Abstracts of Working Documents ...642

Annex 1 – Participants List ...649

Annex 2: TASACS: A Toolbox for Age‐structured Stock Assessment using Catch and Survey data ...655

Annex 3: Technical Minutes RGWIDE ...674

(10)

Executive Summary

The Working Group (WG) on Widely Distributed Stocks (WGWIDE) met in ICES headquarters, Copenhagen 2 – 11 September 2008. Participants were scientists from Spain, Russia, UK (Scotland, England & Wales), Netherlands, Norway, Faroe Islands, Iceland, Ireland, Portugal and France. The WG reports on the status and considera‐

tions for management of NEA Mackerel, Sardine and Blue Whiting, Southern and Western Horse Mackerel stocks and Norwegian Spring Spawning Herring. The ad‐

vice for North Sea horse mackerel was not updated this year.

Special requests from Norway/EC/Faroe Island and Ireland regarding

the management of mackerel in the North‐East Atlantic which included a review of reference points;

long term management of Blue whiting which included references to the stock struc‐

ture

were also addressed by WGWIDE and reported here.

Northeast‐Atlantic (NEA) Mackerel. This species is distributed in the whole ICES area and currently supports one of the most valuable European fisheries (with around 500 kt annual landings). Mackerel is fished by a variety of fleets (ranging from open boats using hand lines on the Iberian coasts to large freezer trawlers and Refrigerated Sea Water (RSW) vessels in the Northern Area. The stock is historically divided into three components, with the North Sea component considered to be over fished since the late 1970s, and the Western component contributing the vast majority of biomass and catch to the stock. The quality of sampling data remains good. The NEA mackerel assessment was treated as an update. The 2007 SSB input for the ana‐

lytical assessment was based on a revised estimate of Mackerel Egg abundance from the 2007 International Survey. Fishing mortality in 2007 is estimated to be above pre‐

cautionary levels. Because of the unknown levels of underreporting in the catch, SSB in recent years cannot be accurately estimated, but indications are that SSB has in‐

creased by 40% since 2004. Variability in recruitment has increased in recent years.

Horse Mackerel. The WG performed an analytical assessment for western horse mackerel. The assessment indicates that the current level of SSB is above that in 1982 which produced the corresponding outstanding year class. The analyses confirms strong recruitment of the 2001 year class however this is not estimated to be of the same order of magnitude as the 1982 year class. The advice for this stock is based on an agreed management plan. An analytical assessment was also conducted for south‐

ern horse mackerel. The 2 surveys were combined and a clear cohort signal was evi‐

dent. The assessment was performed using Flexible Forward Age‐Structured Assessment program (ASAP). This estimated a recent increase in SSB and a quite sta‐

ble overall fishing mortality. The assessment estimated above average 2004 recruit‐

ment.

Sardine. An update assessment using the single area AMCI model was conducted including some exploration of model settings. The assessment indicated that SSB in 2007 decreased 8% compared to 2006 due to successive low recruitments in the last three years (2005 – 2007). Fishing mortality increased by 18% from 2006 to 2007, re‐

flecting the small increase of catches and the decrease in stock abundance although it is still near a historical low. In addition, the WG considered alternatives for manage‐

(11)

Norwegian spring spawning herring. It is the largest herring stock in the world. It is largely migratory and distributed throughout large parts of the NE Atlantic. The productivity of the stock has increased in the last 20 years as a result of strong year classes being produced more often. The WG undertook a bench‐mark assessment of this stock. This was performed using recently developed assessment tools software (TASACS).The results from assessing the stock using a number of age‐structured models were evaluated and the WG agreed on an assessment based on a VPA. This last model estimated spawning‐stock biomass well above Bpa in 2008 and near the highest in the recent time series. Management advice was provided based on the agreed management plan.

Blue whiting. It is a pelagic gadoid that is widely distributed in the eastern part of the North Atlantic. Due to the large population size, its considerable migratory capa‐

bilities and wide spatial distribution, much remains to be understood regarding the stock composition and dynamics. The assessment this year was considered an update and was performed using the Stochastic Multi‐species (SMS) model. Two alternative configurations of the 2007 WG options for SMS model were tested this year. In addi‐

tion results were compared with XSA, TISVPA and ICA (FLICA). The four models estimated a steep decrease in recruitment in the most recent years with the age‐1 abundance in 2007 at a historically low value. All the models estimate a large SSB reduction since 2004 and high mean F. To keep the SSB above precautionary reference points advised landings will require a reduction in F of 60% compared to F in 2008. A new draft management plan that takes into account recent low recruitment was put forward by the Coastal states in 2008 and was evaluated by the WG by means of simulation testing.

(12)

(13)

1 Introduction

1.1 Terms of Reference

Generic ToRs for Review and Advice Drafting Groups in 2008

The review process will have a different role compared to previous years. The new review process will aim to provide a review of the scientific finding and the devel‐

opment of a final advice that can be submitted to the Advisory Committee for ap‐

proval. This shall be done in two distinct processes.

a ) The first part is done by review groups that are constituted of independent experts and are not involved with the expert group report to be reviewed:

i ) The review groups shall ensure the quality of the analyses that is pro‐

duced by the Expert Group(s). The Group shall review the quality of the assessment work carried out by the Expert Group(s) and write technical minutes of the main findings in the review. These Technical Minutes are part of the Expert group report. The review shall consider whether the analysis integrates all relevant knowledge;

b ) The second step is advice drafting. The first draft advice is developed by the senior advisors supported by chairs from the expert groups and the Se‐

cretariat.

This draft is considered by an advice drafting group that review the draft advice and ascertain that the advice is

• in accordance with the advisory principles established by ACOM and as

• laid down in the MoUs with Clients

• relevant and answering the request

• understandable

• credible

• according to the standard form and format of advice

ii ) for fisheries advice, produce consolidated eco‐region advice that, to‐

gether with single stock summaries can be submitted to the Advisory Committee for adoption.

Generic ToRs for Fish Stock Assessment Working Groups

For AFWG, HAWG, NWWG, NIPAG, WGWIDE, WGBFAS, WGNSSK, WGNSDS, WGSSDS, WGHMM and WGANC ToRs (1)‐(4):

1 ) Assemble national data on relevant fisheries and environmental data a ) Input and quality check all input data and where possible input into

the INTERCATCH database;

b ) Produce an overview of the sampling activities on a national basis (if possible derived from the INTERCATCH database);

c ) Recommend specific actions to be taken to improve the basis for the advice in future

(including improvements in data collection);

(14)

d ) When appropriate, conduct a Data Compilation Workshop as part of the expert group meeting where stakeholders are invited to contribute data including data from non‐traditional sources. At these workshops stakeholders can also contribute to data preparation and evaluation of data quality. Data that are to be included in the analysis of the Expert Group shall satisfy quality criteria established by ACOM;

2 ) Update time‐series of relevant fisheries and environmental data:

a ) catches (landings, discards, bycatch)( – by fisheries/fleets). Where mis‐

reporting is considered significant, provide qualitative and where possible quantitative information and describe the methods used to obtain the information.

b ) fishing effort (by fisheries/fleets) c ) surveys

d ) environmental drivers

3 ) Update description of major regulatory changes (technical measures, TACs, effort control and management plans) and report on evaluations of their (po‐

tential) effects.

4 ) Produce a brief report of the work carried out by the Working Group. This re‐

port should summarise for the stocks and fisheries where the item is relevant:

a ) Stock status and catch options b ) Mixed fisheries considerations c ) Ecosystem effects of fisheries

d ) Regulatory changes in the fisheries which have consequences for the assessment or projections

e ) Agreed or proposed management plans f ) Species interaction effects

For AFWG, HAWG, NWWG, NIPAG, WGWIDE in addition consider

5 ) Update the agreed analytical method for those stocks where a benchmark as‐

sessment is required to assess the state of the stocks and short term outlooks or update the agreed indicator(s) of stock trends

ToR for WGWIDE

2007/2/ACOM13 The Working Group on Widely Distributed Stocks [WGWIDE]

(Chair: Beatriz Roel*, UK) will be established and will meet at ICES Headquarters, 2–

11 September 2008 to:

a ) compile, update, analyse and document time‐series of relevant fisheries, environmental data and regulatory changes (see generic ToRs)

b ) summarise the findings for the following stocks (see generic ToR 4):

i ) NEA Mackerel

ii ) Western and southern Horse mackerel iii ) Norwegian Spring Spawning herring iv ) Blue whiting

(15)

WGWIDE will report by 12 September 2008 for the attention of ACOM. This Group continues work previously undertaken by WGMHSA and WGNPBW. Anchovy assessments are moved to WGANC.

1.2 List of Participants

Beatriz Roel (Chair) United Kingdom Pablo Abaunza Spain

Esther Abad Spain

Paula Alvarez Spain Frans van Beek Netherlands Sergei Belikov Russian Federation Thomas Brunel Netherlands Andrew Campbell Ireland

Høgni Debes Faroes

Erwan Duhamel France

Afra Egan Ireland

Pavel Gasyukov Russian Federation Asta Gudmundsdóttir Iceland

Jens Christian Holst Norway Detlev Ingendahl Germany Svein A. Iversen Norway Teunis Jansen Denmark Igor Karpusheveskiyi Russia

Alexander Krysov Russian Federation Charlotte Main United Kingdom Jacques Massé France

Manolo Meixide Spain

Eugene Mullins Ireland Alberto Murta Portugal

Jose de Oliveira United Kingdom

Are Salthaug Norway

Sonia Sanchez Spain Begoña Santos Spain

John Simmonds United Kingdom Dankert Skagen Norway

(16)

Alexandra Silva Portugal Jens Ulleweit Germany

Nikolay Timoshenko Russian Federation Morten Vinther Denmark

Sytse Ybema Netherlands

1.3 Quality and Adequacy of Fishery and Sampling data 1.3.1 Sampling Data from Commercial Fishery

The working group again carried out a brief review of the sampling data and the level of sampling on the commercial fisheries. Sampling coverage for mackerel con‐

tinued to increase and now stands at 87%, exceeding the long‐term average (82%).

The proportion of the horse mackerel catch sampled has considerably decreased from 72% in 2006 to 62% in 2007 with divisions where sampling is considered inadequate.

Sardines continue to be well sampled with samples provided by Portugal, Spain and France.

Information on long term trends in sampling effort were not given in the previous WGNPBW reports. However, tables with the total figures since 2000 were added at the beginning of the Norwegian spring spawning herring and the blue whiting sec‐

tions. Overall, Norwegian spring spawning herring and blue whiting sampling cov‐

ers 94% and 87% of the total catch, respectively.

It should be noted that the information on the percentage of catch sampled depends entirely on the accuracy of the sampled catch figure provided by the relevant coun‐

tries.

In general, to facilitate age‐structured assessment, samples should be obtained from all countries with catches of the relevant species.

The sampling programmes on the various species are summarised as follows:

(17)

Mackerel

YEAR TOTALCATCH (WG CATCH)

% CATCH COVERED BY SAMPLING PROGRAMME*

NO.

SAMPLES NO.MEASURED NO.AGED

1992 760,000 85 920 77,000 11,800

1993 825,000 83 890 80,411 12,922

1994 822,000 80 807 72,541 13,360

1995 755,000 85 1,008 102,383 14,481

1996 563,600 79 1,492 171,830 14,130

1997 569,600 83 1,067 138,845 16,355

1998 666,700 80 1,252 130,011 19,371

1999 608,928 86 1,109 116,978 17,432

2000 667,158 76 1,182 122,769 15,923

2001 677,708 83 1,419 142,517 19,824

2002 717,882 87 1,450 184,101 26,146

2003 617,330 80 1,212 148,501 19,779

2004 611,461 79 1,380 177,812 24,173

2005 543,486 83 1,229 164,593 20,217

2006 472,652 85 1,604 183,767 23,467

2007 579,379 87 1,267 139,789 21,791

*Percentage related to working group catch.

In 2007, 87% of the total catch was covered by national sampling programmes, a small increase on the figure for the previous year (85%). This is despite a significant fall in the number of samples compared with recent years. Denmark, Germany, Ice‐

land, Norway, Portugal, Russia, Scotland and Spain all sampled over 95% of their catch with Ireland and the Netherlands achieving rates over 85%. As in previous years, England & Wales sample a small fraction (6%), corresponding to the handline fishery in area VIIe and VIIf. The remaining countries (of which France, the Faroes, Northern Ireland, Sweden and Poland had significant catches) failed to sample any catches.

(18)

The sampling summary of the mackerel catching countries is shown in the following table:

COUNTRY OFFICIAL CATCH

% CATCH COVERED BY

SAMPLING PROGRAMME

NO.

SAMPLES

NO.

MEASURED NO.AGED

Belgium 1 0 0 0 0

Denmark 25,223 99 34 2,875 2,875

Faroe Islands 13,430 0 0 0 0

France 20,038 0 0 0 0

Germany 18,221 97 54 15,090 1,765

Iceland 36,706 99 18 298 286

Ireland 49,259 94 40 7,436 2,443

Jersey 6 0 0 0 0

Lithuania 7 0 0 0 0

Netherlands 24,244 85 50 4,902 1,250

Norway 131,691 98 196 19,618 898

Poland 978 0 0 0 0

Portugal 2,605 100 273 21,732 1,497

Russia 35,408 100 87 23,105 1,288

Spain 62,946 100 379 26,162 4,888

Sweden 3,858 0 0 0 0

UK (England & Wales) 14,654 6 51 6,942 962

UK (Northern Ireland) 5,545 0 0 0 0

UK (Scotland) 113,490 97 85 11,629 3,639

Total 558,310 87 1,267 139,789 21,791

* Percentage based on Working Group catch

(19)

The following table describes the mackerel sampling levels by relating numbers measured and aged to the size of the catch in each ICES division. Areas where insuf‐

ficient sampling was carried out include IIIa (1,485t), VIIc (1,260t), VIIk (495t), VIIIa (5,444t), VIIId (674t). This was also the case with VIIIa,d in previous years. No sam‐

pling was carried out in areas IIIb,c,d and VIIa,g,h although the corresponding catches were minor.

AREA OFFICIAL CATCH

WG CATCH

NO SAMPLES

NO AGED

NO MEASURED

NOAGED/

1000 TONNES*

NO MEASURED/

1000 TONNES*

IIa 65,002 64,992 99 1,362 23,084 20 360

IIIa 1,485 1,485 0 0 0 0 0

IIIb 2 2 0 0 0 0 0

IIIc 3 3 0 0 0 0 0

IIId 2 2 0 0 0 0 0

IVa 247,958 256,152 271 4,617 28,502 18 115

IVb 908 1423 14 1,265 1,345 1,390 1,480

IVc 233 132 1 25 64 110 270

Va 7,802 7,802 4 112 119 10 20

Vb 97 97 2 100 200 1,030 2,050

VIa 111,996 111,193 90 3,161 14,875 28 133

VIIa 9 71 0 0 0 0 0

VIIb 20,220 23,801 29 1,971 6,139 97 304

VIIc 1,359 1,260 0 0 0 0 0

VIId 3,358 7,407 6 150 685 40 200

VIIe 541 2,535 31 215 4,849 397 8,963

VIIf 805 805 25 872 2,635 1,083 3,273

VIIg 27 27 0 0 0 0 0

VIIh 33 20 0 0 0 0 0

VIIj 22,871 26,894 42 1,531 9,333 70 410

VIIk 495 495 0 0 0 0 0

VIIIa 5,710 5,444 0 0 0 0 0

VIIIb 3,827 3,827 23 1,057 1,410 280 370

VIIIcE 46,557 46,557 224 2,446 15,429 50 330

VIIIcW 6,899 6,899 62 827 4,281 120 620

VIIId 730 674 0 0 0 0 0

IXaN 6,773 6,773 71 583 5,107 90 750

IXaCN 2,605 2,605 273 1,497 21,732 570 8,340

Total 558,307 579,377 1,267 21,791 139,789 39 250

* Based on official catches

(20)

Horse Mackerel

The following table shows a summary of the overall sampling intensity on horse mackerel catches in recent years:

YEAR TOTALCATCH (WG CATCH)

% CATCH COVERED BY SAMPLING PROGRAMME*

NO. SAMPLES

NO.MEASURED NO.AGED

1992 436,500 45 1,803 158,447 5,797

1993 504,190 75 1,178 158,954 7,476

1994 447,153 61 1,453 134,269 6,571

1995 580,000 48 2,041 177,803 5,885

1996 460,200 63 2,498 208,416 4,719

1997 518,900 75 2,572 247,207 6,391

1998 399,700 62 2,539 245,220 6,416

1999 363,033 51 2,158 208,387 7,954

2000 272,496 56 1,610 186,825 5,874

2001 283,331 64 1,502 204,400 8,117

2002 241,336 72 1,768 235,697 8,561

2003 241,830 79 1,568 200,563 12,377

2004 216,361 68 1,672 213,066 16,218

2005 234,876 78 2,315 241,629 15,866

2006 215,277 72 1,623 231,344 12,009

2007 187,995 62 1,321 174,897 10,749

* Percentage related to Working Group catch

There was a considerable decrease in overall sampling for horse mackerel from 2006 to 2007. This is the lowest sampling level since 2000. As usual the large numbers of measured fish are due to intensive length measurement programs in the southern areas. In 2007, 76% of the horse mackerel measured were from Division IXa.

Countries that carried out sampling were Germany which covered 4% of the catches and Denmark, Ireland, the Netherlands, Norway, Portugal and Spain covered 501 – 00 of their catches. France, UK and Lithuania took considerable catches without provid‐

ing any samples or data to the Working Group. The lack of sampling data for rela‐

tively large portions of the horse mackerel catches continues to have a serious effect on the accuracy and reliability of the assessment and the Working Group remain con‐

cerned about the low number of fish that are aged. Last year it was the first time Lithuania reported horse mackerel catches. Their main catches were taken in Division VIIb.

(21)

The following table shows the most important horse mackerel catching countries and the summarised details of their sampling programme in 2006:

%CATCH SAMPLED*

NO.

SAMPLES

NO.

MEASURED

NO.AGED

Belgium 6 0

Denmark 7,872 86 12 445 445

Faroe Islands 478 0

France 18,097 0

Germany 5,871 3 16 2,480 742

Ireland 30,092 91 43 8,117 2,980

Lithuania 5,763 0

Netherlands 60,237 68 57 8,651 1,425

Norway 5,425 74 15 574 166

Portugal 10,380 100 750 120,730 1,681

Spain 27,319 98 428 33,900 3,342

Sweden 129 0

UK (England & Wales) 12,403 0

UK (Scotland) 1,403 0

Sum (WG catch) 187,994 62 1,321 174,897 10,749

(22)

The following tables have information broken down by horse mackerel stock.

The horse mackerel sampling intensity for the Western stock (areas) was as follows:

%CATCH SAMPLED*

NO.

SAMPLES

NO.

MEASURED

NO.AGED

Denmark 7,617 86 6 399 399

Faroe Islands 478

France 12,748

Germany 5,784 4 16 2,480 743

Ireland 30,091 91 43 8,117 2,948

Lithuania 5,467

Netherlands 29,083 50 32 4,649 800

Norway 4,182 97 15 574 166

Spain 14,257 100 254 20,811 2,367

Sweden 76

UK (England & Wales) 5,482

UK (Scotland) 778

Sum (WG catch) 123,408 57 366 37,030 7,423

(23)

The horse mackerel sampling intensity for the North Sea stock (IVb,c, VIId and the eastern part of IIIa) was as follows:

%CATCH SAMPLED*

NO.

SAMPLES

NO.

MEASURED

NO.AGED

Belgium 6

Denmark 255 71 5 46 46

France 5,349

Germany 87

Ireland 1

Lithuania 296

Netherlands 31,154 92 25 4,002 625

Norway 1,243

Sweden 53

UK (Scotland) 625

Sum (WG catch) 41,164 61 163 30 4,048

The horse mackerel sample intensity is higher than usual and is caused by the Neth‐

erlands which has an extensive sampling program takes 77% of the catches.

The horse mackerel sampling intensity for the Southern stock (areas) was as follows:

%CATCH SAMPLED*

NO.

SAMPLES

NO.

MEASURED

NO.AGED

Portugal 13,043 95 174 13,089 975

Spain 103,380 100 750 120,730 1,681

Sum (WG catch) 23,323 97 924 133,819 2,656

(24)

The horse mackerel sampling intensity by division was as follows:

Area Official catch

WG catch

No samples

No sampled

No

measured No aged/1000

tonnes

No measured/

1000tonnes

IIa 0 0

IIIa 148 148 0 0 0

IIIb 4 4 0 0 0

IIIc 22 22 0 0 0

IVa 8198 6996 15 166 574 24 82

IVb 1126 1119 6 46 46 41 41

IVc 21333 8118 5 125 626 15 77

Va 0 0

VB 366 366 0 0 0

VIa 24474 25948 36 1954 5304 75 204

VIb 331 331 0 0 0

VIIa 51 51 0 0 0

VIIb 26608 29601 18 1120 3423 38 116

VIIc 1517 1159 0 0 0

VIId 20529 29808 20 500 3376 17 113

VIIe 13248 18908 16 466 3138 25 166

VIIf 260 260 21 950 3381 3654 13004

VIIg 0.01 0.01 0 0 0

VIIh 4295 4295 3 171 171 40 40

VIIj 10981 8866 0 0 0

VIIk 185 185 0 0 0

VIIIa 11251 11251 3 228 228 20 20

VIIIb 3174 3174 10 294 999 93 315

VIIIcE 4817 4817 148 1110 11660 230 2421

VIIIcW 9141 9141 96 963 8152 105 892

VIIId 3 3 0 0 0 0 0

IXaN 12046 12046 174 975 13089 81 1087

IXaCN 2700 2700 535 760 73701 281 27297

IXaCS 5580 5580 76 500 5716 90 1024

IXaS 2337 2337 139 421 41313 180 17678

SUM 184725 187995 1321 10749 174897 57 930

(25)

Sardine

The following table shows a summary of the overall sampling intensity over recent years on the catches of the sardine stock in VIIIc and IXa.

YEAR TOTALCATCH % CATCH COVERED BY SAMPLING PROGRAMME*

NO. SAMPLES

NO.MEASURED NO.AGED

1992 164,000 79 788 66,346 4,086

1993 149,600 96 813 68,225 4,821

1994 162,900 83 748 63,788 4,253

1995 138,200 88 716 59,444 4,991

1996 126,900 90 833 73,220 4,830

1997 134,800 97 796 79,969 5,133

1998 209,422 92 1,372 123,754 12,163

1999 101,302 93 849 91,060 8,399

2000 91,718 94 777 92,517 7,753

2001 110,276 92 874 115,738 8,058

2002 99,673 100 814 96,968 10,231

2003 97,831 100 756 93,102 10,629

2004 91,886 100 932 112,218 9,268

2005 97,345 100 925 116,400 9,753

2006 87,848 100 927 122,185 9,165

2007 94,648 100 797 97,187 8,607

• Percentage related to Working Group catch

The sampling intensity for all sardine catching countries was as follows:

% CATCH COVERED BY

SAMPLING PROGRAMME

NO.

SAMPLES

NO.

MEASURED NO.AGED

Portugal 64,500 100 447 59,611 4,908

Spain 31,968 100 350 37,576 3,699

France 24,009 67 42 2,878 1,194

Ireland 82 0 0 0 0

UK (England & Wales) 2,576 0 0 0 0

Total 123,135 91,4 839 100,065 9,801

(26)

Norwegian Spring Spawning Herring (NSSH)

YEAR TOTALCATCH % CATCH COVERED BY SAMPLING PROGRAMME

NO. SAMPLES

NO.MEASURED NO.AGED

2000 1,207,201 86 389 55956 10901

2001 766,136 86 442 70005 11234

2002 807,795 88 184 39332 5405

2003 789,510 71 380 34711 11352

2004 794,066 79 503 48784 13169

2005 1,003,243 86 459 49273 14112

2006 968,958 93 631 94574 9862

2007 1,266,993 94 476 56383 14661

94% of the total catch was covered by national sampling programmes. The following table gives a summary of the sampling activities of the NSSH catching countries. The sampling coverage by country is between 74 to 100%. No sampling were carried by Greenland, Ireland and Poland but catches of these countries are representing to‐

gether only 1.2% of the total catch.

:

% CATCH COVERED BY

SAMPLING PROGRAMME

NO.

SAMPLES

NO.

MEASURED NO.AGED

Denmark 22,911 100 8 1038 1005

Faroe Islands 64,251 89 9 900 900

Germany 6,038 74 13 5271 895

Greenland 4,897 0 0 0 0

Iceland 173,621 80 66 2661 2493

Ireland 6,411 0 0 0 0

Norway 779,089 100 212 15897 7098

Poland 4,333 0 0 0 0

Russia 162,434 91 160 29600 2028

Scotland 13,244 100 1 143 67

The Netherlands 29,764 100 7 873 175

Total 1,266,993 94 476 56383 14661

Shown in the following table are the NSSH sampling levels by relating numbers measured and aged to the size of the catch in each ICES division.

AREA OFFICIAL CATCH

WG CATCH

NO SAMPLES

NO AGED

NO MEASURED

NOAGED/

1000 TONNES****

NO MEASURED/

1000

IIa 1,205,106 1,205,106 417 12715 50454 11 42

IIb 8,291 8,291 23 313 4200 38 507

Va 46,743 46,743 29 933 1029 20 22

Vb 2,312 2,312 6 600 600 260 260

XIVa 4,541 4,541 1 100 100 22 22

Total 1,266,993 1,266,993 476 14661 56383 12 45

(27)

Blue Whiting

YEAR TOTALCATCH % CATCH COVERED BY SAMPLING PROGRAMME

NO. SAMPLES

NO.MEASURED NO.AGED

2000 1,412,928 * 1136 125162 13685

2001 1,780,170 * 985 173553 17995

2002 1,556,792 * 1037 116895 19202

2003 2,321,406 * 1596 188770 26207

2004 2,377,569 * 1774 181235 27835

2005 2,026,953 * 1833 217937 32184

2006 1,966,140 * 1715 190533 27014

2007 1,610,090 87 1399 167652 23495

* no figures given

87% of the total catch was covered by national sampling programmes. The sampling summary of the blue whiting catching countries is shown in the following table. No sampling were carried out by France, Lithuania and Sweden, representing together 1.7% of the total catch. All other countries are sampling for length and age with the exception of Germany which failed to provide age readings.

% CATCH COVERED BY

SAMPLING PROGRAMME

NO.

SAMPLES

NO.

MEASURED NO.AGED

Denmark 48,659 99 28 1381 1381

Faroe 317,859 99 29 5337 2892

France 16,639 0 0 0 0

Germany 34,404 * 45 10669 0

Iceland 236,538 97 94 9833 4015

Ireland 31,132 99 19 3595 1704

Lithuania 9,812 0 0 0 0

Norway 539,587 100 353 30223 5915

Portugal 3,897 50 241 32358 1559

Russia 236,369 48 218 27553 2029

Scotland 43,540 77 7 1242 310

Spain 13,557 100 283 26914 2020

Sweden 464 0 0 0 0

The Netherlands 77,634 101 82 18547 1670

Total 1,610,090 87 1399 167652 23495

* no figure given

The following table describes the blue whiting sampling levels by relating numbers measured and aged to the size of the catch in each ICES division.

(28)

AREA OFFICIAL CATCH

WG CATCH

NO SAMPLES

NO AGED

NO MEASURED

NO AGED/

1000 TONNES*

NO MEASURED/

1000 TONNES*

IIa 119,570 119,478 247 3467 28232 29 236

IIb 2,624 2,624 46 810 5366 309 2045

IIIa 334 334 9 142 684 425 2048

IVa 60,590 60,590 62 1678 5408 28 89

IVb 182 182 34 659 2418 3622 13291

Va 34,077 34,077 9 529 933 16 27

Vb 289,513 290,146 85 2939 8736 10 30

VIa 307,092 305,579 117 3248 22299 11 73

VIb 281,288 281,709 96 2164 12934 8 46

VIIb 821 821 0 0 0 0 0

VIIc 434,563 437,273 97 2989 13745 7 32

VIId 0 120 0 0 0 0 0

VIIIabd 3 3 0 0 0 0 0

VIIIc+IXa 17,453 17,453 524 3579 59272 205 3396

VIIj 96 58 0 0 0 0 0

XII 40,506 40,506 65 1291 5998 32 148

XIIb 4,848 4,848 0 0 0 0 0

XIVb 16,529 16,529 8 0 1627 0 98

Total 1,610,090 1,612,331 1399 23495 167652 15 104

(29)

1.3.2 Importance of métier identification.

A métier is defined as a fishing activity which is characterised by one catching gear and a group of target species operating in a given area during a given season, within which the catches taken by any unit of fishing effort account for the same pattern of exploitation by species and size group (Tétard et al., 1995). Later, the ‘ICES Study group on the Development of Fishery‐based forecast’ (SGDFF, 2003) established ‘mé‐

tier’ as:

• Fleet: a physical group of vessels sharing similar characteristics in terms of technical features.

• Fishery. Group of vessel voyages targeting the same (assemblage of) spe‐

cies using the same gear.

• Métier: homogeneous division of a fishery by vessel type.

The identification of métiers allows to have a more complete understanding (qualita‐

tively and quantitatively) of the distribution of fishing effort between resources. The changes observed in effort may be due either to seasonal patterns of species distribu‐

tion, fishing regulations and temporal restrictions, resource depletion, market forces or technical development. A case of resource depletion was described for purse sein‐

ers in the Galician area, when they were directed to horse mackerel during the scar‐

city of sardine (during 1996 –1 999); another example is the French purse seiners in the Bay of Biscay that due to the recent collapse of anchovy they are now incrementing the catches of sardine.

As it is has been presented in the WD‐Abad et al (2008), focused on the purse seine Spanish fleet, the main objective of identifying métiers within a fleet, is to establish feasible fishing units to be used in effort‐based management and to deepen the knowledge of the whole fishing system. Taking into account that the new European DCR (Data Collection Regulation) is based on métiers rather than stocks, defining métiers within a fleet is completely necessary.

In the working document, the methodology recommended is cluster multivariate analysis (CLARA and PAM methods). Six trips types with high consistency and a regular continuity along the time series were obtained for the Northern Coastal Span‐

ish fleet operating in the ICES subdivision VIIIc and IXa North in the period analysed (20032 – 005). Also, the fleet analysis gave as results two homgeneous groups, one of big vessels and other of small ones. Before establishing métiers, it is necessary to fol‐

low the fishery behavior since the recent collapse of the anchovy stock. So, these six trips types have been defined instead of métiers for sampling and management pur‐

poses.

1 ) Purse seine trips targeting sardine.

2 ) Purse seine trips targeting anchovy.

3 ) Purse seine trips targeting mackerel.

4 ) Purse seine trips targeting horse‐mackerel.

5 ) Purse seine trips targeting Sparidae.

6 ) Purse seine trips targeting mixed species (others)

All landings and onboard catches information from Purse seine fleet will be split in these 6 units for the Spanish Information and Sampling Programme but only units from 1 to 4 will be included in the length on market Sampling.